feat(realtime): add generationTick event for billing updates

packages/sdk/src/realtime/client.ts

@@ -12,7 +12,7 @@ import {
   type SubscribeEvents,
   type SubscribeOptions,
 } from "./subscribe-client";
-import type { ConnectionState, SessionIdMessage } from "./types";
+import type { ConnectionState, GenerationTickMessage, SessionIdMessage } from "./types";
 import { WebRTCManager } from "./webrtc-manager";
 
 async function blobToBase64(blob: Blob): Promise<string> {
@@ -99,6 +99,7 @@ export type RealTimeClientConnectOptions = z.infer<typeof realTimeClientConnectO
 export type Events = {
   connectionChange: ConnectionState;
   error: DecartSDKError;
+  generationTick: { seconds: number };
 };
 
 export type RealTimeClient = {
@@ -203,6 +204,11 @@ export const createRealTimeClient = (opts: RealTimeClientOptions) => {
       };
       manager.getWebsocketMessageEmitter().on("sessionId", sessionIdListener);
 
+      const tickListener = (msg: GenerationTickMessage) => {
+        emitOrBuffer("generationTick", { seconds: msg.seconds });
+      };
+      manager.getWebsocketMessageEmitter().on("generationTick", tickListener);
+
       await manager.connect(inputStream);
 
       const methods = realtimeMethods(manager, imageToBase64);

packages/sdk/src/realtime/types.ts

@@ -64,6 +64,17 @@ export type GenerationStartedMessage = {
   type: "generation_started";
 };
 
+export type GenerationTickMessage = {
+  type: "generation_tick";
+  seconds: number;
+};
+
+export type GenerationEndedMessage = {
+  type: "generation_ended";
+  seconds: number;
+  reason: string;
+};
+
 export type SessionIdMessage = {
   type: "session_id";
   session_id: string;
@@ -84,6 +95,8 @@ export type IncomingWebRTCMessage =
   | ErrorMessage
   | SetImageAckMessage
   | GenerationStartedMessage
+  | GenerationTickMessage
+  | GenerationEndedMessage
   | SessionIdMessage;
 
 // Outgoing message types (to server)

packages/sdk/src/realtime/webrtc-connection.ts

@@ -2,6 +2,7 @@ import mitt from "mitt";
 import { buildUserAgent } from "../utils/user-agent";
 import type {
   ConnectionState,
+  GenerationTickMessage,
   IncomingWebRTCMessage,
   OutgoingWebRTCMessage,
   PromptAckMessage,
@@ -29,6 +30,7 @@ type WsMessageEvents = {
   promptAck: PromptAckMessage;
   setImageAck: SetImageAckMessage;
   sessionId: SessionIdMessage;
+  generationTick: GenerationTickMessage;
 };
 
 export class WebRTCConnection {
@@ -157,6 +159,17 @@ export class WebRTCConnection {
         return;
       }
 
+      if (msg.type === "generation_tick") {
+        this.websocketMessagesEmitter.emit("generationTick", msg);
+        return;
+      }
+
+      if (msg.type === "generation_ended") {
+        // Handled internally — not surfaced as a public event.
+        // Devs use connectionChange for disconnect and error for insufficient credits.
+        return;
+      }
+
       if (msg.type === "session_id") {
         this.websocketMessagesEmitter.emit("sessionId", msg);
         return;